1. Technical Field
The present invention relates to a semiconductor device with a thin film transistor (hereinafter, referred to as a “TFT”), an electronic apparatus, a method of manufacturing a semiconductor device, and a method of manufacturing an electronic apparatus, and particularly to improvement of a TFT fabricated by using a liquid phase process.
2. Related Art
A TFT is made of thin films such as a conducting film, an insulating film, and a semiconductor film. A chemical vapor deposition (hereinafter, abbreviated as “CVD”) method and a sputtering method are used for formation of such films. Formation of mask patterns using a resist material and etching are required for patterning thin films. Therefore, expensive manufacturing equipment is necessary for manufacturing a semiconductor device with a TFT It is also necessary to take environmental measures.
Manufacturing a TFT (organic TFT) using a liquid material has been investigated to meet these needs. For example, JP-A-2004-63975, which is an example of related art, discloses a method of forming a conducting film of an electrically conductive material, an insulating film of an epoxy resin, a polyimide resin, an acrylic resin, or the like, and a semiconductor film of an organic semiconductor material of pi-conjugated low molecular weight molecule (small molecule) or high molecular weight polymer by using liquid phase processes.
A liquid phase process, however, has a difficulty in forming a TFT having a very small area, resulting in the provision of a TFT having such a structure that an end of a gate electrode layer is over source and drain electrodes with a gate insulating layer interposed therebetween.
In formation of a gate electrode layer by a droplet discharge method (ink-jet method) or the like, if the minimum line width is, for example, 10 μm, the channel length is shortened until it reaches about several μm. As a result, a TFT has a large total area of the portions in which source and drain electrodes are under the gate electrode layer.
The large total area of the portions in a TFT causes an increase in parasitic capacitance between the gate electrode layer and the source and drain electrodes, thereby reducing the performance of the TFT as a switching element.
If an end of the gate electrode layer extends over the source and drain electrodes, an electric field concentration occurs at the end of the gate electrode layer. As a result, dielectric breakdown is likely to occur in portions of a gate insulating layer sandwiched by the end of the gate electrode layer and the source and drain electrodes.